Percussion-tool



A. c. DAVID SON.

PERCUSSION T0 0L.

APPLICATION FILED MAR. 29. 1919.

131,69, Patented Oct. 2&1919

unirnn snares PATENT ornicn ARTHUR C. DAVIDSON, OEBROOKIYN, NEW YORK, ASSIGNOB; *JlO UNIVERSAL TOOL COMPANY, INCORPORATED,.OF NEw YORK, N. Y., A CORPO- RATION OF DELAWARE.

PERCUSSION-TOOL.

Specification of Letters Patent. Patented 0013.28, 1919.

Application filed March 29, 1919. Serial ire/286,112.

To all whom it may concern:

Be it knownthat I, Aniimn (l. DAVIDSON, a citizen of the United States, and resident of the borough of Brooklyn, in the county of Kings and State of N ew York, have invented certain new and useful improve ments in Percussion-Tools, of which the following is a specification.

This invention relates to percussion tools and has particular reference to tools such as rivet sets, hammers, chisels, etc., which are subjected to very heavy deterioration by reason of the large number of hammer blows they have to withstand. Tools of the class to which this invention relates are ordinarily used in pneumatic machines such as hammers, riveters, etc, and the object of the invention is to provide a tool which will not be subject to breakage, which will have a longer life, and which when damaged by the blows of the pneumatic piston, can readily be repaired without being thrown away.

The invention is shown herein in connection with a rivet set, wherein Figure 1 is a figure partly in section showing the manner of positioning a rivet set in jaws carried by the end of thebody of the riveter,

Fig. 2 is a sectional view of an improved rivet set embodying the invention, and

Fig. 3 is an end view.

Many attempts have heretofore been made to prevent rivet sets from breaking where the shank joins the body, or in the groove where the riveter jaws engage, and various shapes and designs of one-piece structures have been made up and tried, but without fully solving the problem. I have discovered during a long series of eXperiments that a two-piece construction is essential, one piece comprising the body which carries the heading recess or other tool formation and exteriorly formed to be held by the riveter jaws, and the other piece being an insert preferably having a short projection beyond the end of the shank for re ceiving the blows from the pneumatic or other power driven piston, and tightly fitting in the shank and head throughout its length and at the bottom. The insert is preferably of length greater than the shank so as to extend in. the head at least to, and preferably beyond the meeting corner of the head and shank. I have discovered that different points the shank and the body,

the requirements are that the body be relatively tough whilethe insert be relatively hard and tough so as to resist percussion due to the hammer without being deformed or upset, and that the insert have a tight fit throughout the distance from the end of the shank to the bottom of the insert.

1 is the body, shown in Figs. 2 and 3 as having the round rivet heading recess 2, and also having a groove 3 for receiving the jaws l carried by the end of the barrel 5 of, for example, a pneumatic riveter. 6 represents a shank of such reduced diameter as to fit within the end of the barrel 5. Here tofore, the failures have largely occurred at or about the region where the reduced shank 6 joins the enlarged body portion 1, and many efforts have been made to prevent these fractures by using high quality steels which would be variously heat treated at in the length of the body, being treated on the shank one way where the shank joins the body, and still another way at the heading end or recess.

According to this invention, the shank 6 is bored to receive a substantially cylindrical insert 7, either the bore or the insert being very slightly tapered so that the insert can be driven in and firmly held, the bore extending at least beyond the juncture of but not necessarily beyond the groove 3 toward the head. This insert for best results will be made of a special hard steel capable of resisting blows without deformation, such as a special chrome vanadium steel intended for very hard parts. This insert will be heat treated according to the requirements of the work, and in any'event will be of such'character as not to expand or upset when hammered. ()ther suitable compositions for the insert are found in nickel steel, chrome nickel steel and tool steel, the particular choice depending upon the nature of the work. The body is constructed of a steel having the necessary tensile strength and toughness to resist deformation by the head of the rivet, but need not necessarily be as hard as the insert 7. Tool steel, ehromevanadium steel and special alloy steels made according to specifications for the particular work, also give excellent results. It is found that the hard steel of the insert does not upset and split the shank, the reason being that the insert is in substantialcontact with the bore pended claims, as

throughout its length and distributes the expansive strains. The insert is preferably madefas shown to project beyond the end of the shank, so as to protect the the hammer. In case the projecting end of the insert gets worn down, it is only necessary to put the tool in a grinder to slightly grind off the end of the shank and re-finish the end of the insert. Thereby, the life of the tool is materially extended.

It will be understood that I do not restrict myself to a rivet set as illustrated herein except as required by the Wording of the ap- I wish to include all equivalent sets, hammers, chippers, or the like, Without specific illustration.

That is claimed,'is:

I 1. A percussion tool comprising a body of relatively tough material provided with working means on one end and an insert in the other end in. driving contact with the body from the inner end of the insert to the outer end of: the body and of relatively hard material substantially more resistant to percussion and upsetting1F than the body and protecting the body om percussion Without 1nter'fering with the transmission 0f copies of this patent my be obtained for driving force to the body.

shank from 2. A percussion tool comprising a body provided withworking means on one end, and a protecting insert in the other end in driving contact with the body from the inner end of the insert to the outer end of the body and of material more resistant to percussion and upsetting than the body. 8. A rivet set comprising a body provided with heading means; and a reduced shank having an insert of material. resistant to percussion extending through the shank and partly through the body in driving contact with the shank and body.

4. A rivet set having a body composed of a relatively tough material having a reduced shank and formed at the end to head a rivet, and an insert of hard material driven through the shank into the body in driving contact with the shank and body from the inner end of the insert to the outer end of the body and projectingbeyond the end of the shank only sufiiciently to take the hammer blow.

Signed at the borough of Brooklyn in the county of Kings and State of New York this 28th day of March A. D. 1919.

ARTHUR V C. DAVIDSON.

five cents each, by addressing the Commissioner of Iatents, Washington,'1). 0." 

